Stationary and mobile vacuum debris collection systems have proven to be useful in a number of industrial and environmental applications. For example, truck-mounted vacuum cleaning systems have long been used to clean a wide variety of debris from areas such as waste collection areas of power plants, steel mills, and other industrial sites.
Typically, vacuum debris cleaning systems have one or more collection chambers into which collected debris material is deposited (such debris collection tanks or hoppers are commonly referred to as “debris bodies” in the art). A high velocity blower or fan generates a stream of air to flow through a flexible hose that induces the debris to flow from the debris collection site through a flexible hose to the debris body in which heavier debris particles are deposited. However, lighter debris particles remain in the air stream and continue to move toward the blower and the exhaust where the air stream is released to the environment.
Filter bags or sock filters are commonly employed to capture such fugitive airborne debris in vacuum cleaning systems. While generally effective at removing debris particles from the air stream, filter bags and sock filters become clogged quickly and, accordingly, must be cleaned and/or replaced frequently, when brought into contact with many types of airborne debris particles.
To improve the performance of bag and sock filtration systems, purge systems that agitate or shake the filters or periodically deliver a charge of compressed air to the filters have been proposed (see, e.g., U.S. Pat. Nos. 4,336,040 and 5,409,512). Unfortunately, in practice most shaker and agitator systems have been shown to make only modest improvements in filter life. Moreover, such systems may require a large number of mechanical and/or pneumatic components and thereby increase the cost of the system as well as the likelihood of system failure.
Another approach to improving the capture of airborne debris particles is to use a cyclone to separate heavier airborne debris particles before the air stream contacts the filter bags. Examples of such systems are described in European Patent Application 0 434 007 and U.S. Pat. No. 5,996,171. Such systems are further exemplified by Guzzler® Ace® vacuum trucks sold by the Federal Signal Corporation (Elgin, Ill., USA—www.elginsweeper.com). While effective in many respects, the effective filter life and efficiency in such serial cyclone separator/baghouse filter systems still often remains shorter than the period of desired operation.
For these and other reasons, there remains a need for improved and alternative devices and systems for handling airborne debris in debris collection systems. The invention provides such devices and systems, debris collection vehicles that incorporate such devices and systems, and methods of using such devices, systems, and vehicles. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.